The prevalence of respiratory distress syndrome among infants weighing less than 1500 grams ranges from 50% to 80%. Bronchopulmonary dysplasia or chronic lung disease occurs in 16% to 28% of these infants. These two conditions, respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD) contribute significantly to neonatal mortality and morbidity. Among infants who have these conditions, but who survive to be discharged from the hospital, further morbidity and mortality have also been reported. The national extent of this excess morbidity and mortality however, is not well described, nor have the risk factors been identified. In order to gain greater insight into the risk factors associated with morbidity and mortality after an infant with RDS and/or BPD is discharged from their initial hospitalization, we propose to examine the 1988 National Maternal and Infant Health Survey with the following specific aims. To determine among infants who experienced RDS and/or BPD in the nursery: a) whether the socioeconomic status of the family is associated with rehospitalization rates for respiratory disorders; b) if exposure to environmental cigarette smoke in the home is associated with increased rehospitalization rates; c) whether infants discharged on apnea monitors have less morbidity and mortality; c) whether infants discharged on supplemental oxygen have better growth and less morbidity; d) whether feeding human milk affects further respiratory morbidity and mortality. The results of these analyses may provide information for the generation of further hypotheses that could be tested in a prospective fashion. In addition, this survey will allow us to provide national postdischarge estimates of the prevalence of respiratory conditions in this high risk group of infants.